The Sun and Your Eyes
Most Americans are aware of the risks of sunburn and skin cancer from the sun’s ultraviolet (UV) radiation. But did you know UV and other radiation from the sun can also harm your eyes? Extended exposure to UV rays has been linked to cataracts, macular degeneration, pingueculae and pterygia (benign growths or lesions that form on the white part of your eye), and photokeratitis (often called snow blindness).
There are three categories of invisible high-energy UV rays:
- UVC rays. These are the highest-energy UV rays and potentially could be the most harmful to your eyes and skin. Fortunately, the atmosphere’s ozone layer blocks virtually all UVC rays.
- UVB rays. These have slightly longer wavelengths and lower energy than UVC rays. These rays are filtered partially by the ozone layer, but some still reach the earth’s surface. In low doses, UVB radiation stimulates the production of melanin (a skin pigment), causing the skin to darken, creating a suntan. But in higher doses, UVB rays cause sunburn that increases the risk of skin cancer. UVB rays can also cause skin discolorations, wrinkles and other signs of premature aging of the skin. Because the cornea appears to absorb 100 percent of UVB rays, this type of UV radiation is unlikely to cause cataracts and macular degeneration, which instead are linked to UVA exposure.
- UVA rays. These are closer to visible light rays and have lower energy than UVB and UVC rays. But UVA rays can pass through the cornea and reach the lens and retina inside the eye. Overexposure to UVA radiation has been linked to the development of certain types of cataracts, and research suggests UVA rays may play a role in the development of macular degeneration.
Recent research suggests the sun’s high-energy visible (HEV) radiation (also called “blue light”) may increase your long-term risk of macular degeneration. According to a European study published in the October 2008 issue of Archives of Ophthalmology, people with low blood plasma levels of vitamin C and other antioxidants appear to be at risk of retinal damage from HEV radiation. This appears to be because HEV rays can penetrate deeply into the eye and cause retinal damage.
The risk of damage to our eyes and skin from solar UV radiation is cumulative, meaning the danger continues to grow as we spend time in the sun throughout our lifetime. With this in mind, it’s especially important for children to protect their eyes from the sun since they generally spend much more time outdoors than adults.
To best protect your eyes from the sun’s harmful UV and HEV rays, always wear good quality sunglasses when you are outdoors. Look for sunglasses that block 100 percent of UV rays and that also absorb most HEV rays. Your eye doctor or optician can help you choose the best sunglass lenses for your needs.
The amount of UV protection sunglasses provide is unrelated to the color and darkness of the lenses. A light amber-colored lens can provide the same UV protection as a dark gray lens. But for HEV protection, color does matter. Most sunglass lenses that block a significant amount of blue light will be bronze, copper or reddish-brown.
But don’t let this information stop you from enjoying the sunny weather! Just make sure you’re wearing the right eye protection to reduce your UV and HEV exposure.